Subscriber&#39;s telephone-circuit.



UNITED STATES Patented December 15, 1903.

1 PAT NT OFFICE.

WILLIAM W..DEAN, or oIIIcAco, ILLINOIS, ASSIGNOR TO KELLOGG swIToH-BOARD AND SUPPLY COMPANY, OF cIIIoAeo, ILLINOIS, A CORPORATION OFILLINOIS.

SUBSCRIBERS TELEPHONE-CIRCUIT.

SPECIFICATION forming part of Letterslatent N 0. 747,331, dated December15, 1903.

Application filedDecember 23,1902. Serial No. 136,334.. (No model.)

T at whom it may concern.-

Be it known that 1, WILLIAM W. DEAN, a citizen of the United States ofAmerica, residing at Chicago, in the county of Cook and State 5 ofIllinois, have invented new and useful Improvements in SubscribersTelephone-Circuits, of which the following is a specification.

My invention relates to anew and improved snbscribers circuit whereby amore efficient l0 operation of the system is secured. In thisarrangement I seek to provide means for preventing the direct flow ofbattery-current through the receiver during conversation or the passagetherethrough of the heavy ringing-current in case the receiver is liftedwhile the generator-current is on the line. I also provide means wherebywhen the subscriber is flashing the supervisory lamp at the centraloffice the battery-current does not make a click or noisein the receiverwhen the linecircuit is broken. I am also enabled in this invention touse a lower resistance-bell than usual and which does not interfere withtransmission. To the accomplishment of these and such other objects asmay hereinafter appear my invention consists in the arrangement andlocation of the various parts, as hereinafter described, andparticularly pointed out in the appended claims, reference being had tothe accompanying drawings, in which the same reference charactersindicate like parts throughout, and in which Figure 1 showsdiagrammatically a com- 5 plete telephonic system embodying myimprovements. Fig. 2 is a simplified diagram of a subseribers line towhich the improved substation-circuit is applied, and Fig. 3 is adetailed view of the hook-switch and its contacts.

Referring first to Fig. l, the telephonelines are shown extending fromthe substations to the central oflice, where they-are fitted with theusual apparatus to permit interconnect- 5 ing them for conversationalpurposes as well as for suitably supervising and attending the saidconnections. The line L, for example, extends in two limbs 2 and 3 tothe springs of the line-cut-off relay R, the former being groundedthrough a branch 4 and the latter being normally connected with aconductor 5, leading to the line-relay R which is connected upon itsopposite side and by means of a conductor 6 with the live pole of acentral and common battery B. Y The line-signal S is controlled by thenormallyopen contacts of the line-relay R Suitable spring-jacks, such asJ, J and J in any desired number are provided with conductors, reachingto the forward contacts of the said cut-off-relay 6c springs, wherebywhen the said cut-off relay is actuated the said jacks are connected tothe external line-circuit. The cut-0E relay may be legged to ground fromthe sleeve-jack conductor, as shown.

The cord-circuit'may be of any suitable type, that shown consisting of apair of plugs P and P having their contacts connected togetherbysuitable flexiblestrands. Acall coming in over the line L,for example,is answered by the insertion of the plug P, which permits current toflow from the battery B through the sleeve supervisory rela; 'rZover thesleevestrand 3 of the cord-circuit, and through the cut-off relay R,which serves to connect the said jacks, as before stated, with theexternal line-circuit and to render the line-signal inoperative. Thesupervisory signal S associated with the plug P, does not respond, owingto the actuation of tip supervisory relay rover the tip-strand t of thecord-circuit and the metallic telephone-line. Ascertaining that one ofthe parties located upon the polystation-line L is desired,the line istested in the usual manner. If idle, the jack-rings are connected withearth and no click is received; but if busy the said rings are connectedwith the live pole of either the battery B or B and a current flows overthe tipstrand li and through the high-resistance and high-impedancetest-relay T, which is actu ated and serves to close a path for currentthrough the primary winding of the operators induction-coil, thusgivinga click in the operators receiver. If idle, the calling-plug 5 Pis inserted, and either the springs 7 or 8 are actuated to connect theringing-generator 9 with one side or the other of the telephone-line toring the desired subscriber. When springs 7 of the ringing-key areactuto;

ated, the cut-off relay R of the line is maintained actuatedoverconductor 9and through resistance-coil,while if the other set ofsprings be actuated the ringing-current itself, which is preferablynegative pulsating in character, serves to maintain the same actuated.It will be understood that by the operation of a set of springs 11 ofany suitable listeningkey the operators head-telephone, the secondary ofher induction-coil, and a suitable condenser may be bridged across thecalling end of the cord-circuit. It will be also apparent that theoperators transmitter 12 is charged from the battery B over the commonlead 6 and conductor 13, the latter conductor containing theretardation-coil 14. After calling the subscriber the sleeve supervisoryrelayr is actuated to complete through its main contact the circuit ofthe supervisory lamp S which is lighted to indicate that the subscriberhas not yet responded. The said relay also completes the tip-strand tfor conversation through its auxiliary contact and cuts off thetest-relay r When the called subscriber responds, the tip supervisoryrelay r is energized by current over the metallic line to extinguishsupervisory lamp S As shown by reference to Fig. 2, the hookswitch 15serves in its raised position to complete a path for steady current overthe conductor 3, through branch 16, containing the retardation -coil 17,preferably of about twenty-five ohms resistance, contact 18, thencethrough the hook, contact 19, and thence through the transmitter 20 andback over line conductor 2 to the central oftice. At the same time anauxiliary path for varying current is provided over said line conductor3 through the condenser 21, receiver 22, switch-hook 15, contact 19,through transmitter 20, and back to the central otfice over conductor 2.Thus during conversation two parallel paths are provided, one opaque tothe passage of varying or voice currents, while the other is opaque tothe passage of steady currents and permits the passage of thevoicecurrents. When the receiver is upon the hook 15, as is normally thecase, the abovementioned paths for current are opened and a path forringing-current through the callbell 23 is provided. This current may betraced from the line-wire 2, through branch 24, containing the bell 23,to lower contact 25 of the hook-switch, through the switch 15, andthence to lower contact 26 and over conductor 27, through condenser 21,and by the way of line conductor 3 back to the central oifice. This isthe path for ringing-current when the subscriber is called from thecentral oflice.

Fig. 3 shows the practical construction of the hook-switch, in which thereceiver is shown upon its hook-lever, the lever being indicated in fulllines as at an intermediate position, while the dotted lines indicateits uppermost and lowermost positions. The

several springs are bunched, as shown, and are suitably insulated fromone another and are secured to a suitable rigid support. The centralspring extends beyond the free ends of the other springs and engages alug upon the switch-hook, whereby said springs are suitably controlledin the vibration of the hook-lever. These springs are preferably givensuch a normal trend or bias that when the lever is depressed thecontacts 18 and 19 do not separate from contact 15 until after thelatter engages contact 26. Byreference to Fig. 2 the effect of this isclearly seen and which consists in completing the sh untabout thereceiver 22 to prevent the flow through said receiver of the extracurrent due to the breakingof the circuit. Likewise the spring 26 may beadjusted to separate from 15 only after contacts 18 and 19 are made; butthis is not essential, since the initial completion of the circuit isnot so objectionable in the receiver. By this arrangement direct currentfrom the central-ofiice battery does not flow through the receiverduring conversation, nor does the heavy ringing-current passtherethrough if the receiver is lifted when the subscriber is beingcalled, since a more ready path is provided through the conductor 16 andlow-resistance impedance-coil 17. Moreover, when the subscriber is,attempting to attract the attention of the operator at the centraloflice by flashing the supervisory lamp the current at breaking thecircuit does not cause a click in the receiver. Again, this circuitpermits the use of a low-resistance bell and also one of low impedance,since it performs no function in transmission. In the case of apolystation-line, as shown at stations 0 and D upon line L the bells maybe connected through the switch-hook from the oppositeline conductors toground. Otherwise the arrangement is substantially the same as describedwith reference to Fig. 2 and substantially as shown at the station Aupon line L.

Although various forms of hook-switches maybe employed, one that isfound suitable for my purposes is shown in my Patent No. 704,697, datedJuly 15, 1902.

Various modifications may be made in my invention without departing fromits scope or principle, and I therefore do not wish to be limited in allrespects to the precise arrangement and combinations shown.

By the term opaque as employed herein, defining a circuitin its relationto the energizing-current, I contemplate a circuit containiug a'condenser or equivalent device which prevents the passage through thecircuit of an appreciable or substantial amount of currentt.hat is, asufficient amount to affeet the operation of the system to anobjectionable degree, and by the term opaque when referring to thetalking currents I contemplate that characteristic of the circuit whichwill prevent the passage of the talkingcurrents therethrough insuflicient amount to materially afiect the transmission ofthetalking-currents through the path containing the telephone-receiver.

The condenser may be replaced by other direct-current interrupterswithout departing from the scope of my invention.

I claim 1. The combination with a telephone-line extending to acentralstation, of an energizing source of electricity at the central stationadapted to be connected therewith, a pair of parallel paths in one ofthe limbs of the telephone-line, a receiver and a condenser included inone of said paths, a choking or impedance coil included in the otherpath, a call-bell connected between the opposite limb and the pathcontaining the receiver and condenser at a point between said receiverand condenser when the receiver is upon the switch, and means foropening said path containing the bell when the receiver is off itsswitch, substantially as described.

2. The combination with a telephone-line extending to the centralstation, of an energizing source of electricity at the central stationadapted to be connected therewith, a pair of parallel paths in one ofthe limbs of the telephone-line, a receiver and a steadycurrentinterrupter included in one of said paths,a chokingorirnpedancecoilconnected in the other path, and a call-bell normallyconnected between the opposite limb and the path containing the receiverand condenser at a point between said receiver and condenser, and meansfor opening said bell branch during conversation, substantially asdescribed.

3. A telephone-substation apparatus comprising the main circuit, saidcircuit having two parallel paths, one path being opaque tovoice-currents and the other opaque to steady currents, areceiver in thepath opaque to steady currents, a condenser also in said path, acall-signaling bell, and means for normally including only said bell incircuit with said condenser, and only the receiver in circuit therewithduring conversation, whereby in an organization of the type describedthe condenser is used for both signaling and talking and the bell is cutout during conversation, substantially as described.

4. The combination with a telephone-line extending to the centralstation, of an energizing source of electricity at the central officeadapted to be connected therewith, a pair of parallel paths in one ofthe limbs of the telephone-line, a receiver and direct-currentinterrupter included in one of said paths, an impedance-coil included inthe other path, a call-bell connected to the path containing thereceiver and interrupter and at a point begizing source of electricityat the central office adapted to be connected therewith, a pair ofparallel paths in one of the limbs of the telephone-line, a receiver andcondenser included in one of said paths, an impedancecoil included inthe other path, and a callbell connected with the path containing thereceiver and condenser at a point between them and having its circuitnormally closed through contacts controlled by the hookswitch of thesubscribers set, substantially as described.

6. The combination with a telephone-line extending to the centralstation, of an energizing source of electricity at the central ofticeadapted to be connected therewith, a pair of parallel paths in one ofthe limbs of the telephone-line, a receiver and direct-currentinterrupter included in onset said paths, an impedance-coil included inthe other path, and a call-bell connected upon one side with the pathcontaining the receiver and interrupter at a point between them and uponthe other side with a suitable return, the circuit of said bell beingcompleted through contacts normally closed by the hook-switch of thesubscribers set, substantially as described.

7. The combination with a telephone-line, of an energizing source ofelectricity at the central office included in the line to furnishcurrent to the substation for conversation, a substation apparatusincluding two paths, one containing a steady-current interrupter to makethe path opaque to the passage of steady currents, and the other pathbeing opaque to the passage of voice-currents, a transmitter in thepathof the steady currents, a telephone-receiver in the path that isopaque to the passage of the steady currents, a signaling-bell normallyconnected with the latter path so as to include the said interrupter inits operating-circuit,and means to out out the said bell duringconversation, substantially as described. I

8. The combination with a telephone-line extending to the centralstation, of an energizing source of electricity at the central stationadapted to be connected therewith, a

pair of parallel paths in one of the limbs of the telephone-line, areceiver and direct-currentinterrupterincluded in one of said paths, achoking or impedance coil included in the other path, and alow-resistance bell normally connected between the opposite limb and thepath containing said receiver and interrupter, and means to prevent saidbell from shunting the telephonic currents to an objectionable degreefrom the talking instruments, substantially as described.

9. The combination with a telephone-line, of an energizing source ofelectricity at the central office included in the line to furnishcurrent to the substation for conversation, a substation apparatusincluding two paths, onecontaining a condenser and the other aretardation coil, a transmitter in the path of steady currents, atelephone-receiver in circuit with the condenser and out of the path ofsteady currents, a signaling-bell normally connected with the pathcontaining the receiver and condenser and so as to include saidcondenserin its operating-circuit, and a hook-switch to cut out saidbell during conversation and to change the circuits from signaling totalking position and vice versa, substantially as described.

10. The combination with a telephone-line, of a central source of onrrent connected therewith, a telephone-receiver at the substation, and ashunt-circuit at the substation closed around the said receiver beforethe main-line circuit is broken, whereby the opening of the main-linecircuit does not objectionably afiect the receiver, substantially asdescribed.

11. The combination with a telephone-line,

of a central source of current connected therewith, a telephone-receiverat the substation, and a shunt-circuit at the substation closed aroundthe said receiver before the main-line circuit is broken at thesubstation, whereby the opening of the main-line circuit does notobjectionably afiect the receiver, substantially as described.

12. The combination with a telephone-subscribers station-circuit, ot' areceiver connected therewith, and means controlled by the switch-hook atthe said station for preventing noise in the receiver during theoperation of the hook-switch, substantially as described.

13. The combination with a telephone-subscribers station-circuit, of areceiver connected therewith, and means controlled by the switch-hook atthe said station for preventing noise in the receiver in the alterationof the circuit arrangement by the hook-switch, substantially asdescribed.

14:. The combination with a telephone-line, of a source of current atthe central oflice, a substation apparatus comprising a transrnittercharged by said source, a receiver, a hookswitch, and means controlledby the hookswitch for preventing undue noise inthe receiver when thecircuit arrangement is altered by the hook-switch, substantially asdescribed.

15. The combination with a telephone-line, of a source of current at thecentral ofiice, a substation apparatus comprising a transmitter chargedby said source, areceiver, a hookswitch, and means at the substation forpreventing undue noise in the receiver when the circuit of said sourceis opened, substantially as described.

16. The combination with a telephone-line, of a source of current at thecentral oflice, a substation apparatus comprising a transmitter chargedby said source, a receiver, and a hook-switch at the substation tocontrol the circuit of said source through the transmitter, and meanscontrolled by said hook-switch for preventing undue noise in thereceiver when the circuit of said source is opened, substantially asdescribed.

17. The combination with a telephone-line, of a source of current at thecentral office, a substation apparatus comprising a'transmitter chargedby said source, a receiver, a hookswitch, and a shunt of the receivercontrolled by the hook switch, substantially as described.

18. The combination with a telephone-line, of a source of current at thecentral oflice, a substation apparatus comprisinga transmitter chargedby said source, a receiver, a hookswitch, the normal contacts of saidhookswitch being closed before-the alternate contacts are opened wherebynoise in the receiver is prevented, substantially as described.

19. The combination with a telephone-line, of a source of currentconnected therewith at the central office, a subscribers station-circuitincluding a receiver connected therein, a switch-hook to change thecircuits from signaling to talking condition and vice versa, and meanscontrolled by the switch-hook for preventing noise in the receiver whenthe circuit of the receiver is closed, substantially as described.

20. The combination with a telephone-line, of a source of currentconnected therewith at the central ofiice, a subscribersstation-circuit, a receiver connected therewith, a switchhook to changethe circuits from signaling to talking condition and vice versa, andmeans controlled by the switch-hook for preventing noise in the receiverwhen the circuit thereof is opened or closed, substantially asdescribed.

21. The combination with a telephone-line, of a source of currentconnected therewith at the central office, a subscribersstation-circuit, a receiver connected therewith, and means forpreventing noise in the receiver when its circuit is closed at thesubstation, substantially as described.

22. The combination with a telephone-line, of a source ofcurrentconnected therewith at the central oflice, a subscribersstation-circuit, a receiver connected therewith, and means forpreventing noise in the receiver when its circuit is open or closed atthe substation, substantially as described.

23. The combination with a telephone-line, of a source ofcurrentconnectcd therewith at the central oifice,a substation apparatuscomprising a transmitter charged by said source, a receiver, ahook-switch, and a shunt of the receiver controlled by the hook-switchto prevent noise in the receiver when its circuit is closed,substantially as described.

24. The combination with a telephone-line, of a source of current at thecentral office, a substation apparatus comprising a transmitter chargedby said source, a receiver, and a shunt of the receiver controlled bythe hookswitch, said shunt being closed before the circuit through thereceiver is opened and said circuit being closed before the shunt isopened in the operation of the hook-switch, substantially as described.

25. The combination with a telephone-line, of an energizing source ofelectricity at the central office included in the line to furnishcurrent to the substation for conversation a of the hook-switch, theportion of said branch between said normal contacts and the connectionthereof with the said receiver-circuit constituting a shunt about thereceiver in the operation of the hook-switch, substantially asdescribed.

Signed by me, at Chicago, county of Cook, State of Illinois, this 19thday of December,

WILLIAM W. DEAN. Witnesses:

GAZELLE BEDER, ROBERT LEWIS AMES.

